In this file photo dated Jan 13, 2023, Jenson Brooksby of the US serves against Britain's Cameron Norrie (not in photograph) during their Auckland Classic tennis tournament men's singles semi-final match in Auckland. (PHOTO / AFP)

NEW YORK - An independent tribunal has suspended American player Jenson Brooksby for 18 months, the International Tennis Integrity Agency (ITIA) said on Tuesday, after finding that he committed three whereabouts failures in a 12-month period.

The 22-year-old, who achieved his highest career ranking of 33rd last year, previously accepted a voluntary provisional suspension and his sanction will be backdated to July 5. The sanction will end on Jan 4, 2025, according to the ITIA.

Brooksby previously told the AP that he had never failed a drug test or taken "bad substances". The ITIA said that Brooksby accepted the first and third missed tests but disputed the second one.

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Missing three in a 12-month period can constitute an anti-doping rule violation, according to the ITIA. Brooksby has 21 days to appeal against the decision to the Court of Arbitration for Sport (CAS).

"The whereabouts program is a vital tool in maintaining a clean sport," ITIA CEO Karen Moorhouse said in a statement. "No one wants players to fall foul of the rules in this way."